###文件操作
#写文件
#w模式每次写入数据时会覆盖之前的数据
with open("./demo6.txt","w",encoding="utf-8") as file :
    file.write("""
HTML5+CSS3网页设置与制作
JavaScript+jQuery交互式Web前端开发
Bootstrap响应式Web开发
PHP+MySQL动态网站开发
""")  

#a模式每次写入数据时会不覆盖之前的数据
with open("./demo6.txt","a",encoding="utf-8") as file :
    file.write("""
Hello World!!!
""")  

